Essential Revision Notes for MRCP Third Edition - PasTest

Cardiology1.4.2 Ventricular septal defect (VSD)VSDs are the most common isolated congenitaldefect (2/1000 births; around 30% of all congenitaldefects); spontaneous closure occurs in 30%–50%of cases (usually muscular or membranous types).As with ASDs, closure may be performed via cardiotomyor percutaneously.Indications for closure• Significant left-to-right shunt• Associated with other defect requiringcardiotomy• Elevated right heart pressure• Endocarditis• Irreversible pulmonary changes may occur from1 year of age, with vascular hypertrophy andpulmonary arteriolar thrombosis, leading toEisenmenger syndrome• Parasternal thrill and pansystolic murmur arepresent. The murmur may be ejection systolic invery small or very large defects. With largedefects the aortic component of the secondsound is obscured, or even a single/palpable S2is heard; a mitral diastolic murmur may occur.The apex beat is typically hyperdynamicOnce the Eisenmenger complex develops, the thrilland left sternal edge (LSE) murmur abate and signsare of pulmonary hypertension regurgitation andright ventricular failure. Surgery should occur earlierto avoid this situation; otherwise a combined heart/lung transplant would be required.• Other cardiac associations of VSD• PDA (10%)• AR (5%)• Pulmonary stenosis• ASD• Tetralogy of Fallot• Coarctation of the aorta• Types of VSD• Muscular• Membranous• AV defect• Infundibular• Into the right atrium (Gerbode defect)1.4.3 Patent ductus arteriosus (PDA)PDA is common in premature babies, particularlyfemale infants born at high altitude; also if maternalrubella occurs in the first trimester. The connectionoccurs between the pulmonary trunk and the descendingaorta, usually just distal to the origin of theleft subclavian artery. PDA often occurs with otherabnormalities.Key features of PDA• A characteristic left subclavicular thrill• Enlarged left heart and apical heave• Continuous ‘machinery’ murmur• Wide pulse pressure and bounding pulseSigns of pulmonary hypertension and Eisenmengersyndrome develop in about 5% of cases. Indometacincloses the duct in about 90% of babieswhile intravenous prostaglandin E 1 may reverse thenatural closure (useful when PDA is associated withcoarctation, hypoplastic left heart syndrome and incomplete transposition of the great vessels, as it willhelp to maintain flow between the systemic andpulmonary circulations). The PDA may also beclosed thoracoscopically or percutaneously.1.4.4 Coarctation of the aortaCoarctation can present in infancy with heart failureor in adulthood (third decade) with hypertension,exertional breathlessness or leg weakness. This‘shelf-like’ obstruction of the aortic arch, usuallydistal to the left subclavian artery, is 2–5 times morecommon in males and is responsible for about 7%of congenital heart defects.21